Naslov
Niobium In Oxalate Complexes: From Discrete Molecules to Heterometallic Supramolecular Structures

Autori
Jurić, Marijana ; Planinić, Pavica ; Brničević, Nevenka

Vrsta, podvrsta i kategorija rada
Poglavlja u knjigama, znanstveni

Knjiga
Niobium: Properties, Production and Applications

Urednik/ci
Wong, Thomas M

Izdavač
Nova Science Publishers

Grad
Haupauge (NY)

Godina
2011

Raspon stranica
191-204

ISBN
978-1-61122-895-3

Ključne riječi
niobium, oxalate, complexes, structures

Sažetak
The oxalate ion, C2O42– is well known in the chemistry of niobium. Oxalic acid was among the first agents used for the dissolution of the melt obtained by the fusion of Nb2O5 and KHSO4. The first niobium(V) oxalate-containing species of the composition M3[NbO(C2O4)3]•nH2O (M = NH4+, Na+, K+, Rb+) were isolated at the beginning of the last century. As found later, niobium atom in these compounds is heptacoordinated by oxygen atoms forming a distorted pentagonal bipyramid. The same coordination polyhedron was found in the ammonium and caesium salts of the diaquabis(oxalato)oxoniobates(V) M[NbO(C2O4)2(H2O)2]•nH2O (M = NH4+, K+, Rb+, Cs+, ½Mg2+), being formed by two bidentate oxalate groups, two water molecules and one oxo-oxygen atom. Specific supramolecular motifs and solvatomorphism have been found within the series of compounds [M(bpy)3]2[NbO(C2O4)3]Cl•nH2O (M = Fe2+, Co2+, Ni2+, Cu2+, Zn2+ ; bpy = 2, 2'-bipyridine) crystallizing in the monoclinic (n = 11) and orthorhombic (n = 12) crystal systems. In the oxalate-bridged heterometallic complexes [{; ; ; M(bpy)2}; ; ; 2(µ-C2O4)][M(bpy)2(µ-C2O4)NbO(C2O4)2]2•0.5bpy•7H2O (M = Cu2+, Zn2+) and [{; ; ; Cu(phen)2}; ; ; 2(µ-C2O4)][Cu(phen)2(µ-C2O4)NbO(C2O4)2]2•8H2O (phen = 1, 10-phenanthroline) one-dimensional motifs in the structures are generated through the ligand stacking interactions. The square-antiprismatic coordination of niobium(IV) atoms was found in the compounds K4[Nb(C2O4)4]•3H2O, K4[Nb(C2O4)4]•4H2O•1/2H2C2O4 and K2(H3NCH2CH2NH3)[Nb(C2O4)4]∙4H2O.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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